1. Field of the Invention
The present invention relates to a key structure and a keyboard having the same; more particular, to a key structure having a scissor assembly and a corresponding keyboard having a backlight, suitable for being adapted in laptop computers.
2. Description of Related Art
As people rely more on computers for daily life, computers are being used under various conditions and environments. For using in shaded areas where lighting is insufficient, keyboards with backlights have been developed to fit the needs.
A key of a conventional illuminated keyboard typically employs a rubber dome arranged like an inverted cup underneath a key cap. The inner bottom portion of the cup is often a closed-ended structure and is usually provided with a conducting pad. When the key cap is pressed, the conducting pad of the rubber dome is depressed and thus establishes electric contact with a conducting circuit, thereby causing the generation of a key stroke signal. Thus, for illuminated keyboard structures that employ backlight outlets underneath the keycaps, the conventional cup-shaped rubber dome will inevitably block the light output of the backlight unit. In addition, the conducting circuit (or conducting section) is also arranged directly below the rubber dome. Such arrangements adversely affect the lighting efficiency of the backlight to the central portion of the key cap. This deficiency led to insufficient and uneven distribution of lighting for the illuminated key structures. Please refer to FIG. 9. A Taiwan patent (patent # TW468833) disclosed an “Improved Light Source Displaying Structure for Keyboard”. The related disclosure discloses a key structure that, when a key cap 24 is pressed, a pivoting mechanism 22 is collapsed by the movement of a sliding portion 222. The collapse of the pivoting mechanism 22 also forces a conducting portion 231 of a flexible conducting member 23 to pass through a thru-hole 213 of a fixing member 21 and abut pre-arranged electrical circuits on a first circuit board 13 to transfer the keying command.
The abovementioned disclosure further includes a display area 121 defined on a substrate 12 for a corresponding key structure 2. Alternatively, a via hole may be formed on any end of the substrate 12. A corresponding light source 141 for the display area 121 may be a luminescence plate or an LED. As can be seen from FIG. 9 and the descriptions, the light source 141 is arranged directly below the flexible conducting member 23. However, the overlapped configuration reduces the light-emitting efficiency of the keyboard.
Please refer to FIG. 10. Another Taiwan patent (patent # TW509955) disclosed an illuminated keyboard 20, which comprises a key switch 22 and a backlight device 23. The key switch 22 is disposed on the housing (not shown) of the illuminated keyboard 20. The key switch 22 includes a seat 222, a membrane circuit board 223, at least one cap 224, at least one elastic member 221, and at least one connecting assembly 225. The seat 222 is provided with a plurality of fixed members 2221. One end of the connecting assembly 225 is connected to fixed members 2221 of the seat 222 in a slideable and rotatable manner, and the other end of the connecting assembly 225 is connected to the cap 224. Thus, the cap 224 can move upward or downward relative to the seat 222. The elastic member 221 is disposed between the membrane circuit board 223 and the cap 224 to support the cap 224. The seat 222 further includes a first through hole 2222 formed thereon corresponding to the elastic member 221.
Please refer back to FIG. 10. The backlight device 23 is disposed beneath the key switch 22 to illuminate it from the bottom thereof The backlight device 23 comprises a light guide 231, a reflector plate 232, and a light source 233. A person skilled in the art can realize the light emission from the backlight device 23 is directly beneath the elastic member 221. However, because light projection is overlapped by the conducting section of the membrane circuit board 223, light projection is partially blocked which reduces the lighting performance. In addition, light beams from the LED for the above-mentioned illuminated keyboard tend to escape from the slit between the cap and the seat, causing visual discomfort to the user.
To address the aforementioned issue of uneven brightness for the keyboard, the arrangement of the light source for the backlight needs to be adjusted. An alternative means is to increase the number of LEDs to enhance the lighting effect. However, both methods are only reactive remedies and raise the manufacturing cost.
To address the above issues, the inventors strive via industrial experience and academic research to present the present invention, which can effectively improve the limitations described above.